The New Strategic Arms Reduction Treaty - or START - recently signed between the United States and Russia, does not specifically address the issue of missile defenses. But the issue is a sore topic between Washington and Moscow.

The New START Treaty sets a limit of 1,550 deployed strategic - or long-range - nuclear warheads. It also sets a limit of 700 operationally deployed strategic nuclear delivery systems such as long-range launchers and heavy bombers. The pact also has what the Obama administration calls strong verification measures - provisions that ensure each side complies with its treaty obligations.

What the treaty does not directly address is the issue of missile defense. But as Daryl Kimball, Executive Director of the Arms Control Association, a private research firm, says, the topic is mentioned.

"We see in this treaty, the New START Treaty, language in the preamble, the non-binding preamble of the treaty, a statement that there is an inter-relationship between strategic offensive missiles and strategic defensive missiles. And Russia has attached a non-binding unilateral statement to this New START Treaty that expresses the view that if Russia believes U.S. missile defense capabilities are affecting Russia's strategic offensive nuclear capabilities, they reserve the right to withdraw from the treaty," he said.

The Russians have consistently argued that the proposed U.S. missile defense system is aimed at them - a view rejected by U.S. authorities.

Defense Secretary Robert Gates addressed the issue during a May 18 appearance before the Senate Foreign Relations Committee. "Under the last administration, as well as under this one, it has been the United States' policy not to build a missile defense that would render useless Russia's nuclear capabilities. It has been a missile defense intended to protect against rogue nations such as North Korea and Iran - or countries that have very limited capabilities," Gates said.

Gates went on to say Russia has been opposed to U.S. plans for missile defense ever since strategic arms talks began in 1969. "It's the latest chapter in a long line of Russian objections to our proceeding with missile defense. And frankly, I think it's because particularly in the 1970s and 1980s and probably equally now, it's because we can afford it and they can't. And we're going to be able to build a good one and are building a good one, and they probably aren't. And they don't want to devote the resources to it, so they try and stop us from doing it through political means," he said.

Gates and other U.S. government officials say nothing in the New START Treaty prohibits Washington from building missile defenses.

But former Secretary of State James Baker, who negotiated much of the 1991 START-One treaty, appearing before the same Senate committee, said the new treaty does limit one possible use of U.S. intercontinental ballistic missile launchers and submarine-based ballistic missile launchers. "Any arms treaty that goes into effect should focus on nuclear weapons reduction and not on missile defense limitations. In the New START Treaty, however, there is at least one clear limitation on U.S. missile defense systems - specifically, Article Five limits the conversion of ICBM and SLBM launchers into launchers for missile defense interceptors," he said.

Baker admits the Obama administration has no plans to transform strategic weapons launchers into missile defense launchers. "The administration believes that it is less expensive to build new systems rather than to convert existing ones. But I'm not so sure how wise it is to restrict future administrations," he said.

Frank Miller, former senior official on the National Security Council [under President George W. Bush] says he was surprised by the treaty limitation. "It's an impediment because the Republicans have been saying all along that they did not want any sort of restrictions on ballistic missile defense in the treaty. And the administration had been assuring them that there would not be any limitations on ballistic missile defense in the treaty - and here it is. Now it's a very minor limitation. It's entirely consistent with the administration's own policies because it said it was not going to expand the ground-based interceptor network in the United States," he said.

Miller says while this is a minor political impediment, the Obama administration will have to work with the Senate to make sure this will not become a stumbling block to ratification.